Because there just aren't enough.
So what's the deal with getting on xbox live? I ideally want to go wireless as my xbox is two floors away but i've got a 40 metre ethernet cable on my amazon wishlist as standby. I've spent the last few hours reading amazon user reviews but pretty much every router's ratings run the gammut from "I got online so fast I jizzed all over the cat!" to "I can't get on the internet, it gave me cancer and I no longer understand the true meaning of Christmas!" Plus, none of them mention xbox live specifically. Which isn't any help at all.
So people, what's your set-up? Would you recommend it? Is wireless all lag-tastic and not worth the extra cost? All offers of help/sarcastic one liners are welcome.